I first had Ubuntu 11.10 installed on a single partition on my 750GB hard drive.

I then partitioned the hard drive to 500GB (for Ubuntu) in ext4 format (what it already was from the clean install of Ubuntu)....and 250GB for Win7 in NFTS format.

Then I installed Win7 onto that 250GB partition. Installation went smoothly and I was successfully booted into Win7 and setting everything up. After I was done doing all the stupid updates from Microsof, I thought I was done and I wanted to go back to Ubuntu.

This is where the problem starts

Of course I reboot and it goes directly to Win7. I research and find that Win7 has overwritten the Ubuntu bootloader, etc etc.. I don't fully understand it.

I download EasyBCD 2.1.2

In EasyBCD, I select "Add New Entry" and select "Linux/BSD" and change the type to "GRUB 2" and name it "Ubuntu"

Next, I go to "BCD Deployment" and select "Install the Windows Vista/7 bootloader to the MBR" and click "Write MBR"

I reboot, select "Ubuntu" and the purple screen comes up, but NOTHING HAPPENS.

If I hit Ctrl+Alt+Del, it goes to the Login menu where it acts normal for about 10-15 seconds, then freezes. It does this repeatedly every time.

MY QUESTION:

What's wrong here? Why can't I load Ubuntu now? Am I going to have to reinstall Ubuntu with Windows, then set up the bootloader with EasyBCD instead of Ubuntu, THEN Win7?

If a purple screen comes up, you've probably configured EasyBCD and the Windows boot manager fine. The problem is with how Ubuntu is starting - perhaps something has been corrupted.
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Mahmoud Al-QudsiApr 24 '12 at 0:51

I am not sure if you are still having this problem, but like Mahmoud said, EasyBCD is not a third party bootloader at all. It sounds like you might have skipped a step in using easybcd to point the bootloader to the right place where Ubuntu is.

First, here is some reading you should skim over:
1. Here is a solution regarding the alert you got. Read that first.
2. Here is a video that shows a walkthrough for using EasyBCD.
3. Here is a detailed guide to adding ubuntu to the windows bootloader and setting the two up using EasyBCD. And it has nice screenshots with explanations.
4. Here is yet another guide for using EasyBCD.

So what you are doing with EasyBCD is adding Ubuntu to the Windows Bootloader. The GRUB2 bootloader is going to be installed on your external hard drive, so what you want to do is point the Windows Bootloader to boot GRUB2, which should point to the partition that is your external. Then, the windows bootloader will pass you off to GRUB, from where you should be able to select ubuntu. It might help to check out the GRUB2 tutorial reference to get an idea of how GRUB works.

If you boot to live CD you can run sudo blkid. Do the IDs of the bootable drive match the one in the error, if so you can use this video and reinstate grub from the liveCD.